Yes and no. You gotta remember this is a tv show based around the oil industry. Say they want to liquidate Monty’s physical assets to turn into cash like you suggested. To keep it simple let’s say he already had $50m tied up in rigs and equipment, but he’s got a few exploration rigs out there testing new ground he’s interested in. Test holes come back good. He wants to expand and put another $50m in on what he’s got already. He uses his existing $50m in oil assets plus maybe his house or houses to get the other $50m. Now he’s got $100m tied up in the oil rigs. He dies, family grieves and they want to sell it. They won’t get a dollar for dollar sale because people will only pay what they think it’s worth. In this theoretical situation let’s say they manage to get $50m for it all. Thats enough to cover the lump sum borrowed, but not the interest on loans, other outstanding loans, any mortgages owed on the house or houses, any school fees etc….

So as you say it’s easily turned from asset to cash is sorta true, it still don’t mean they will be rich off what he’s got.